We present detailed results of Swift observations of the nearby TeV-detected blazar Mrk 421, based on the rich archival data obtained during 2005 March–2008 June. The best fits of the 0.3–10 keV spectra were mainly obtained using the log-parabolic model, yielding low spectral curvatures expected in the case of the efficient stochastic acceleration of particles. During strong X-ray flares, the position of the synchrotron spectral energy distribution peak was beyond 8 keV for 41 spectra, while it sometimes was situated at the UV frequencies in quiescent states. The photon index at 1 keV exhibited a broad range, and the values were observed during the strong flares, hinting at the possible presence of a jet hadronic component. The spectral parameters were correlated in some periods, expected in the framework of the first- and second-order Fermi accelerations of X-ray emitting particles, as well as in the case of turbulence spectrum. The 0.3–10 keV flux and spectral parameters sometimes showed very fast variability down to the fluctuations by 6–20% in 180–960 s, possibly related to the small-scale turbulent areas containing strongest magnetic fields. X-ray and very high-energy fluxes often showed correlated variability, although several occurrences of more complicated variability patterns are also revealed, indicating that the multifrequency emission of Mrk 421 could not be generated in a single zone.

We present the results from the timing and spectral study of Mrk 421 based mainly on the Swift data in the X-ray energy range obtained during the time interval 2015 December-2018 April. The most extreme X-ray flaring activity on the long-term, daily and intraday timescales was observed during the 2-month period which started in 2017 December when the 0.3-10 keV flux exceeded a level of 5×10 −9 erg cm −2 s −1 , recorded only twice previously. While the TeV-band and X-ray variabilities mostly were correlated, the source often varied in a complex manner in the MeV-GeV and radio-UV energy ranges, indicating that the multifrequency emission of Mrk 421 could not be always generated in a single zone. The longer-term flares at X-rays and γ-rays showed a lognormal character, possibly indicating a variability imprint of the accretion disk onto the jet. A vast majority of the 0.3-10 keV spectra were consistent with the log-parabolic model, showing relatively low spectral curvature and correlations between the different spectral parameters, predicted in the case of the first and secondorder Fermi processes. The position of the synchrotron spectral energy distribution (SED) peak showed an extreme variability on diverse timescales between the energies E p <0.1 keV and E p >15 keV, with 15% of the spectra peaking at hard X-rays and was related to the peak height as S p ∝E α p with α∼0.6, which is expected for the transition from Kraichnan-type turbulence into the "hard-sphere" one. The 0.3-300 GeV spectra showed the features of the hadronic contribution, jet-star interaction and upscatter in the Klein-Nishina regime in different time intervals.

[1] For the weakly ionized E layer plasma, a generalized Charney-Obukhov equation for magnetized Rossby waves is derived. This magnetized Rossby wave is produced by the dynamo electric field and represents the ionospheric generalization of tropospheric Rossby waves in a rotating atmosphere by the spatially inhomogeneous geomagnetic field. The basic characteristics of the wave are given. The modified Rossby velocity and Rossby-Obukhov radius are introduced. The mechanism of self-organization into solitary vortical nonlinear structures is examined. The mechanism of a self-organization of solitary structures is the result of the mutual compensation of wave dispersion and interaction through the scalar and Poisson bracket convective nonlinearities in the nonlinear wave equation. As a result, the solitary structures are anisotropic, containing a circular vortex superimposed on a dipole perturbation. The degree of anisotropy sharply increases when the vortex size approaches the so-called intermediate geostrophic size.

We present the results from a detailed spectral and timing study of Mrk 421 based on the rich archival Swift data obtained during 2009–2012. Best fits of the 0.3–10 keV spectra were mostly obtained using the log-parabolic model showing the relatively low spectral curvature that is expected in the case of efficient stochastic acceleration of particles. The position of the synchrotron spectral energy density peak E p of 173 spectra is found at energies higher than 2 keV. The photon index at 1 keV exhibited a very broad range of values a = 1.51–3.02, and very hard spectra with a < 1.7 were observed during the strong X-ray flares, hinting at a possible hadronic jet component. The spectral parameters varied on diverse timescales and showed a correlation in some periods, which is expected in the case of first- and second-order Fermi acceleration. The 0.3–10 keV flux showed strong X-ray flaring activity by a factor of 3–17 on timescales of a few days–weeks between the lowest historical state and that corresponding to a rate higher than 100 cts s−1. Moreover, 113 instances of intraday variability were revealed, exhibiting shortest flux-doubling/halving times of about 1.2 hr, as well as brightenings by 7%–24% in 180–720 s and declines by 68%–22% in 180–900 s. The X-ray and very high-energy fluxes generally showed a correlated variability, although one incidence of a more complicated variability was also detected, indicating that the multifrequency emission of Mrk 421 could not be generated in a single zone.

No abstract